1. Field of the Invention
This invention relates to a windshield defroster system for a vehicle, and more particularly to a windshield defroster system for a vehicle which is particularly useful for obtaining a sufficient defrosting effect in a vehicle having a windshield mounted at a relatively large angle to the vertical.
2. Description of the Prior Art
A vehicle is generally provided with a windshield defroster for blowing over the windshield conditioned air introduced from an air conditioner in order to remove or prevent frost on the windshield.
Conventionally, the windshield defroster system includes a defroster duct which is disposed on the rear side of the cowl box and has an air plenum for blowing out conditioned air on the upper side thereof as disclosed in Japanese unexamined Utility Model Publication No. 57(1982)125619, for instance. In the conventional defroster system, the direction of the conditioned air blown from the air plenum of the defroster duct depends upon the direction of the approach of the defroster duct formed along the rear side of the cowl box and is controlled so that conditioned air impinges upon the windshield at a predetermined portion at a predetermined angle to flow along the windshield over a desired range.
To improve the profile of a vehicle, the lower edge of the windshield is sometimes positioned more forward than usual so that the windshield is at a larger angle to the vertical. In order to utilize the interior space of the cowl box for disposing a ventilation air passage or a wiper system, generally the lower edge of the windshield is fixed to the upper side of the front portion of the cowl box with the cowl box being arranged to project toward the passenger compartment to a large extent. Accordingly, in the case of the conventional defroster system, conditioned air cannot be caused to impinge upon the windshield at a desired height and in a desired direction, and as a result, the lower portion of the windshield cannot be sufficiently defrosted.
The above problem may be overcome by displacing the rear side of the cowl box below the lower edge of the windshield. However, this approach involves a different problem of the length of the cowl box (as measured in the longitudinal direction of the vehicle) being inherently shortened since the engine room cannot be narrowed, and accordingly, the displacement of a front panel to be accommodated by deformation of the cowl box upon collision is minimized. This is undesirable with respect to preventing the windshield falling out. At the same time, if the interior space of the cowl box is narrowed, the ventilation air passage and/or the wiper system cannot be disposed in the cowl box.